<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>symbol</title>
</head>
<body>
    <script>
        //创建Symbol
        let s = Symbol();
        // console.log(s, typeof s);
        let s2 = Symbol('尚硅谷');
        let s3 = Symbol('尚硅谷');
        //Symbol.for 创建
        let s4 = Symbol.for('尚硅谷');
        let s5 = Symbol.for('尚硅谷');

        //不能与其他数据进行运算
        //    let result = s + 100;
        //    let result = s > 100;
        //    let result = s + s;

        // USONB  you are so niubility 
        // u  undefined
        // s  string  symbol
        // o  object
        // n  null number
        // b  boolean

    </script>
</body>
</html> 